The Elusive Ellshaw (The Saint TV Series)

Plot
After telling the Saint that she's just seen her husband who'd disappeared months earlier, she's murdered. She was once secretary to a wealthy man, in whose house Simon's a guest. Very quickly, he's shot, though not critically. Simon knows these 2 events are connected, but he just doesn't know why... yet.

Origin
This episode was adapted from the novella of the same name from the 1934 book The Saint Goes On.